Endocrine Abstracts

The onset of diabetes mellitus caused by insulin deficiency and insulin resistance is simultaneous with the onset of disorders in lipid and carbohydrate metabolism. Phospholipids are subjected to major alterations in the lipid structures. The data on composition of phospholipids in diabetes mellitus are discordant. The work was initiated to study concentrations of phospholipids in blood of patients with type 1 and type 2 diabetes mellitus. 24 patients with type 1 DM (T1DM) and 34 patients with type 2 DM (T2DM) were recruited for the study. Blood glucose, lipid profiles and blood serum phospholipids were measured. The chloroform-methanol mixture was used to extract the phospholipids. Thin-layer chromatography was used to fractionate them. In patients with T2DM the total phospholipid fractions were found to decrease as compared to the controls (103.63 ± 4.744 µg of phosphorus/mg of protein vs 207.6 ± 4.4 µg of phosphorus/mg of protein). In T1DM patients the total phospholipid fractions were reduced as compared to the controls. As to individual phospholipid fractions in T1DM and T2DM, the alterations were found oppositely directed. Thus, acidic phospholipids, such as phosphatidylinositol (PI) and sphingomyelin (SPH) increased, while the neutral ones, to name phosphatidylethanolamine (PE) and phosphatidylcholine (PC) decreased as compared to the controls. Intensity of acyl residuals of all phospholipid fractions is subject to alterations in insulin deficiency. Transacylation as a chain-termination in fatty acid synthesis in phospholipids is impaired due to inhibition of the acylase reaction with activation of phospholipases to result in suppression of acyl group synthesis. The reduction in synthesis of choline-containing phospholipids can be explained by the disorders in methylation of phosphatidylethanolamine which is a precursor in the process. Failure of the metabolic pathways to reuse exogenous choline due to the deficiency of ATP, A coenzyme, pyridoxal phosphate and other co-factors of lipid metabolism in insulin deficiency could be another cause for the disorder of phospholipid synthesis in diabetes. The increase in lysophosphatidylcholine in diabetes can be associated with the peroxidation of phosphatidylcholine and the disorders in diacyl phospholipid forms. Disorders in major and minor components of phospholipids take place in type 1 DM and type 2 DM. As the result, concentrations of total phospholipids change to result in the lipid metabolism dysregulation.